JP6493031B2 - Positively charged toner - Google Patents

Description

  The present invention relates to positively chargeable toners, and more particularly to capsule toners.

  Patent Document 1 discloses a toner using a quaternary ammonium compound as a charge control agent.

JP 2014-48501 A

  However, it is difficult to form a high-quality (particularly, low fog density) image stably with the technique disclosed in Patent Document 1 alone.

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a positively chargeable toner capable of stably forming a high-quality (for example, low fog density) image.

  The positively chargeable toner according to the present invention includes a plurality of toner particles including a core and a shell layer formed on the surface of the core. The shell layer contains a first resin and a second resin. The first resin contains one or more repeating units having an amide group. The second resin comprises one or more repeating units having a quaternary ammonium cation. When a mixture of 100 parts by mass of a standard carrier and 10 parts by mass of the toner is stirred using a shaker mixer under an environment of temperature 23 ° C. and humidity 60% RH, the charge amount of the toner at the time of stirring for 3 minutes Is equal to or higher than the charge amount of the toner at the time of stirring for 30 minutes and 20 μC / g or more. When the charge amount distribution of the toner carried on the developing roller is measured, the arithmetic mean value X and the standard deviation Y in the charge amount distribution measured have the relationship of the formula “Y / X ≦ 3.5”. Fulfill.

  According to the present invention, it is possible to provide a positively chargeable toner capable of stably forming high-quality (for example, low fog density) images.

  Hereinafter, embodiments of the present invention will be described in detail. The toner according to the present embodiment is a positively chargeable toner and can be suitably used for developing an electrostatic latent image. The toner of the present embodiment is a powder including a plurality of toner particles (particles each having a configuration to be described later). The toner may be used as a one-component developer. Alternatively, the two-component developer may be prepared by mixing the toner and the carrier using a mixing device (for example, a ball mill). In order to form a high quality image, it is preferable to use a ferrite carrier as a carrier. Moreover, in order to form a high quality image over a long period of time, it is preferable to use magnetic carrier particles including a carrier core and a resin layer covering the carrier core. In order to produce magnetic carrier particles, the carrier core may be formed of a magnetic material, or the magnetic particles may be dispersed in a resin layer. In order to form a high quality image, the amount of toner in the two-component developer is preferably 5 parts by mass or more and 15 parts by mass or less, and 8 parts by mass or more and 12 parts by mass with respect to 100 parts by mass of the carrier. It is more preferable that

  The toner particles included in the toner according to the exemplary embodiment include a core (hereinafter, referred to as a toner core) and a shell layer (capsule layer) formed on the surface of the toner core. The shell layer covers the surface of the toner core. The shell layer may cover the entire surface of the toner core or may partially cover the surface of the toner core. An external additive may be attached to the surface of the toner core or shell layer. Also, a plurality of shell layers may be laminated on the surface of the toner core. If necessary, external additives may be omitted. Hereinafter, toner particles before the external additive adheres are referred to as toner base particles. Moreover, the material for forming a shell layer is described as shell material.

  The toner according to the present embodiment can be used, for example, to form an image in an electrophotographic apparatus (image forming apparatus). Hereinafter, an example of an image forming method by the electrophotographic apparatus will be described.

  First, an electrostatic latent image is formed on a photosensitive member (for example, a surface layer portion of a photosensitive drum) based on image data. Next, the formed electrostatic latent image is developed using a developer containing toner. In the developing step, toner (charged toner) on a developing sleeve (for example, a surface layer portion of a developing roller in a developing device) is attached to the electrostatic latent image of the photosensitive member to form a toner image on the photosensitive member. Then, in the subsequent transfer step, after the toner image on the photosensitive member is transferred to the intermediate transfer member (for example, transfer belt), the toner image on the intermediate transfer member is further transferred to the recording medium (for example, paper). Thereafter, the toner is heated to fix the toner on the recording medium. As a result, an image is formed on the recording medium. For example, a full color image can be formed by superposing four color toner images of black, yellow, magenta and cyan.

The toner according to the present embodiment is a positively chargeable toner having the following configuration (1).
(1) When a mixture of 100 parts by mass of standard carrier and 10 parts by mass of toner is stirred using a shaker mixer under an environment of temperature 23 ° C. and humidity 60% RH, the toner is charged at the time of stirring for 3 minutes the amount (hereinafter referred to as the charge amount Q _3), the charge amount of the toner at the time of stirring for 30 minutes at (hereinafter, charge amount to as Q ₃₀₎ or more and 20 [mu] C / g or more. When the charge amount distribution of the toner carried on the developing roller is measured, the arithmetic mean value X and the standard deviation Y in the measured charge amount distribution satisfy the relationship of the formula “Y / X ≦ 3.5”. The method of measuring the charge characteristics (charge amount Q ₃ , charge amount Q ₃₀ , and charge amount distribution) of the toner is the same method as the embodiment described later or an alternative method thereof. The charge characteristics of the toner can be adjusted by changing the type or amount of the shell material.

The toner having the above configuration (1) has a charge amount distribution of coefficient of variation (= Y / X) of 3.5 or less. Further, in the toner having the above structure (1), satisfying the charge amount Q ₃ the relation between the charge amount Q ₃₀ Togashiki "Q ₃₀ ≦ Q _3". The inventors have found that when an image is formed using a toner having such charge characteristics (charge amount Q ₃ , charge amount Q ₃₀ , and charge amount distribution), fogging hardly occurs. Further, in the toner having the above structure (1), the charge amount Q ₃ is 20 [mu] C / g or more. When stirring for 3 minutes, the charge amount (charge amount Q ₃ ) of the toner becomes 20 μC / g or more. For this reason, the toner having the above configuration (1) is excellent in charge rising characteristics. Incidentally, stable high quality in order to form a (particularly, low fog density) images, it is more preferable charge amount Q ₃ is equal to or less than 40 .mu.C / g.

The toner particles contained in the toner according to the exemplary embodiment have the following configuration (2).
(2) The shell layer contains a first resin and a second resin. The first resin comprises one or more repeating units having an amide group. The second resin comprises one or more repeating units having a quaternary ammonium cation.

  When the resin constituting the shell layer contains a repeating unit having a quaternary ammonium cation, there is a tendency for the charge rising characteristics of the toner to be improved (the charge amount is saturated early). The quaternary ammonium compounds are less colored than nitrogen-containing heterocyclic compounds (more specifically, nigrosine or imidazole etc.). Therefore, when the quaternary ammonium compound is contained in the color toner, the quaternary ammonium compound is unlikely to inhibit the color development of the color toner. In addition, when the resin constituting the shell layer contains a repeating unit having an amide group, the charge amount distribution of the toner tends to be sharp. When the toner particles contained in the toner have the configuration (2), the charging characteristics of the toner can be easily adjusted to the charging characteristics defined in the configuration (1).

Formula (1) shows an example of a repeating unit having a quaternary ammonium cation (NR ₄ ⁺ ). Further, in Equation (2) shows an example of a repeating unit having an amide group (-CO-NR _2). N in each of Formula (1) and Formula (2) respectively independently shows the repeating number of a repeating unit.

  By forming an image using the toner having the above configuration (1), it becomes easy to stably form an image of high image quality (particularly, low fog density) (see Tables 1 and 2 described later). In order to form a high-quality (especially low fog density) image stably using toner, it is preferable that the toner contains toner particles having the composition (2) in a proportion of 80% by number or more. It is more preferable to include at a ratio of 90 number% or more, and it is further preferable to include at a ratio of 100 number%.

  The shell layer preferably covers an area of 50% or more and 99% or less of the surface area of the toner core, and preferably 70% or more and 95% or less, in order to achieve both heat resistant storage stability and low temperature fixability of the toner. More preferably, the area is covered. The shell layer may be a film having no graininess or may be a film having a graininess. When resin particles are used as the material for forming the shell layer, it is thought that if the material (resin particles) is completely dissolved and cured in the form of a film, a film without a granular feeling is formed as the shell layer. Be On the other hand, if the material (resin particles) is not completely dissolved but cured in a film-like form, a film (a film having a granular feeling) having a form in which resin particles are two-dimensionally connected is formed as a shell layer. it is conceivable that. In addition, the entire shell layer is not necessarily integrally formed. The shell layer may be a single membrane or an assembly of a plurality of membranes (islands) spaced apart from one another.

  In order to form a high-quality (particularly low fog density) image stably using a toner, the shell layer substantially comprises a first resin (a resin containing one or more repeating units having an amide group) And a second resin particle substantially composed of a second resin (a resin containing one or more repeating units having a quaternary ammonium cation). The ratio of the first resin particles in the shell layer is 0.5% by mass or more and 5.0% by mass or less in order to stably form a high quality image (particularly, low fog density) using a toner. And it is preferable that the ratio of the 2nd resin particle in a shell layer is 95.0 to 99.5 mass%. The ratio (unit: mass%) of resin particles in the shell layer can be calculated based on the formula “100 × (mass of resin constituting the resin particles) / (mass of all resins constituting the shell layer)”.

  By dispersing the toner core in a solution in which the shell material is dissolved or dispersed, a dispersion of the toner core is obtained. When the shell material is polymerized in the dispersion of the toner core, it is preferable that the toner core be anionic and the shell material be cationic. In the dispersion of the toner core, the anionic shell core is electrically attracted to the anionic toner core, whereby the shell layer is easily formed on the surface of the toner core by in-situ polymerization. In addition, it is possible to form a uniform shell layer on the surface of the toner core without using a surfactant (or with only a small amount of surfactant).

  The zeta potential can be used as an index indicating the size of the anion or cation. In order to strengthen the bond between the toner core and the shell layer, it is preferable that the zeta potential of pH 4 of the toner core is smaller than 0 V and the zeta potential of pH 4 of toner particles is larger than 0 V. The zeta potential of pH 4 of the toner core is It is more preferable that the zeta potential of the toner particles be 5 mV or less. In order for the toner core to have strong anionic property, it is preferable that the toner core contains a polyester resin. The method of measuring the zeta potential is the following method or an alternative thereof.

<Method of measuring zeta potential>
0.2 g of a sample (for example, toner core or toner), 80 g of ion-exchanged water, and 20 g of a nonionic surfactant having a concentration of 1% by mass (“K-85”, polyvinyl pyrrolidone, manufactured by Nippon Shokubai Co., Ltd.) Use and mix. Subsequently, the sample is uniformly dispersed in the liquid to obtain a dispersion. Subsequently, dilute hydrochloric acid is added to the obtained dispersion to adjust the pH of the dispersion to 4, and a dispersion of pH 4 is obtained. Then, using a zeta potential and particle size distribution analyzer (“Delsa Nano HC” manufactured by Beckman Coulter, Inc.), the temperature is 25 ° C. and pH 4 by electrophoresis (more specifically, electrophoresis using a laser Doppler system). The zeta potential of the sample in the dispersion is measured.

  Next, the toner core (binder resin and internal additive), the shell layer, and the external additive will be described in order. Unnecessary components may be omitted depending on the application of the toner. The evaluation results (values indicating the shape, physical properties, etc.) of the powder (more specifically, toner core, toner base particles, external additive, toner, etc.) have a considerable number of particles unless specified. The number average of the values measured for Further, the particle diameter of the powder is the circle equivalent diameter of the particle (the diameter of a circle having the same area as the projected area of the particle) unless otherwise specified. Hereinafter, “system” may be added after the compound name to generically generically refer to the compound and its derivative. When a “system” is added after the compound name to represent a polymer name, it means that the repeating unit of the polymer is derived from the compound or its derivative. Moreover, acryl and methacryl may be generically called "(meth) acryl" generically.

<Suitable Thermoplastic Resin>
Examples of thermoplastic resins that constitute toner particles (particularly, toner core or shell layer) include styrene resins and acrylic acid resins (more specifically, acrylic acid ester polymers, methacrylic acid ester polymers, etc.), Olefin resin (more specifically, polyethylene resin or polypropylene resin etc.), vinyl resin (more specifically, vinyl chloride resin, polyvinyl alcohol, vinyl ether resin, N-vinyl resin etc.), polyester resin, polyamide resin Or urethane resin can be suitably used. Also, a copolymer containing one or more repeating units derived from the same monomer as any repeating unit of the above resin (more specifically, a styrene-acrylic acid resin or a styrene-butadiene resin, etc.) It can be suitably used as a thermoplastic resin that constitutes toner particles.

  The thermoplastic resin is obtained by polycondensation or cocondensation polymerization of one or more thermoplastic monomers (more specifically, an acrylic acid type monomer or a styrene type monomer, etc.). The thermoplastic monomer is a monomer that becomes a thermoplastic resin by homopolymerization.

  The styrene-acrylic acid resin is a copolymer of one or more styrene monomers and one or more acrylic monomers. In order to synthesize a styrene-acrylic acid-based resin, for example, styrene-based monomers and acrylic acid-based monomers as shown below can be suitably used. By using an acrylic acid type monomer, a carboxyl group can be introduced into a styrene-acrylic acid type resin. Further, by using a monomer having a hydroxyl group (more specifically, p-hydroxystyrene, m-hydroxystyrene, or (meth) acrylic acid hydroxyalkyl ester), the hydroxyl group can be introduced into the styrene-acrylic acid resin. . The acid value of the resulting styrene-acrylic acid resin can be adjusted by adjusting the amount of the acrylic acid monomer used. Moreover, the hydroxyl value of the styrene-acrylic acid type resin obtained can be adjusted by adjusting the usage-amount of the monomer which has a hydroxyl group.

  Preferred examples of the styrenic monomer include styrene, α-methylstyrene, p-hydroxystyrene, m-hydroxystyrene, vinyl toluene, α-chlorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, Or p-ethylstyrene.

  Preferred examples of the acrylic acid-based monomer include (meth) acrylic acid, (meth) acrylic acid alkyl ester, or (meth) acrylic acid hydroxyalkyl ester. Preferred examples of (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, (meth) acrylic Examples include n-butyl acid, iso-butyl (meth) acrylate, or 2-ethylhexyl (meth) acrylate. Preferred examples of (meth) acrylic acid hydroxyalkyl ester include 2-hydroxyethyl (meth) acrylic acid, 3-hydroxypropyl (meth) acrylic acid, 2-hydroxypropyl (meth) acrylic acid, or (meth) acrylic The acid 4-hydroxybutyl is mentioned.

  The polyester resin is obtained by polycondensation or cocondensation polymerization of an alcohol and a carboxylic acid. As an alcohol for synthesizing a polyester resin, for example, a dihydric alcohol (more specifically, a diol or a bisphenol or the like) or a trivalent or higher alcohol can be suitably used as shown below. As a carboxylic acid for synthesizing a polyester resin, for example, a divalent carboxylic acid or a trivalent or higher carboxylic acid as shown below can be suitably used. Moreover, when synthesize | combining polyester resin, the acid value and hydroxyl value of polyester resin can be adjusted by changing the usage-amount of alcohol, and the usage-amount of carboxylic acid, respectively. When the molecular weight of the polyester resin is increased, the acid value and the hydroxyl value of the polyester resin tend to decrease.

  Preferred examples of diols are ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, or polytetramethylene glycol.

  Preferable examples of bisphenols include bisphenol A, hydrogenated bisphenol A, bisphenol A ethylene oxide adduct, or bisphenol A propylene oxide adduct.

  Preferred examples of trihydric or higher alcohols include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, and 1,2,4-butane. Triol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane or 1,3,5- Trihydroxymethylbenzene is mentioned.

  Preferred examples of the divalent carboxylic acid include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, azelaic acid, malonic acid , Succinic acid, alkylsuccinic acid (more specifically, n-butylsuccinic acid, isobutylsuccinic acid, n-octylsuccinic acid, n-dodecylsuccinic acid, or isododecylsuccinic acid, etc.), or alkenylsuccinic acid (more specifically Examples thereof include n-butenylsuccinic acid, isobutenylsuccinic acid, n-octenylsuccinic acid, n-dodecenylsuccinic acid, and isododecenylsuccinic acid).

  Preferred examples of trivalent or higher carboxylic acids include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylene carboxyl) Methane, 1,2,7,8-octane tetracarboxylic acid, pyromellitic acid, or Empol trimer acid can be mentioned.

  The above-mentioned divalent or trivalent or higher carboxylic acid may be transformed into an ester-forming derivative (more specifically, an acid halide, an acid anhydride, or a lower alkyl ester, etc.). Here, "lower alkyl" means an alkyl group having 1 to 6 carbon atoms.

<Suitable thermosetting resin>
Examples of thermosetting resins that constitute toner particles (in particular, shell layers) include melamine resins, urea resins, sulfonamide resins, glyoxal resins, guanamine resins, aniline resins, polyimide resins (more specifically, In particular, maleimide polymers or bismaleimide polymers, etc.) or xylene resins can be suitably used.

  The thermosetting resin is obtained by polycondensation or cocondensation polymerization of one or more thermosetting monomers. Moreover, a thermosetting resin can also be synthesize | combined by a thermoplastic monomer by using a crosslinking agent. The thermosetting monomer is a monomer that becomes a thermosetting resin by homopolymerization.

  Preferred examples of the thermosetting monomer include methylolmelamine, melamine, methylolated urea (more specifically, dimethylol dihydroxy ethylene urea etc.), urea, benzoguanamine, acetoguanamine or spiloganamine.

[Toner Core]
The toner core contains a binder resin. In addition, the toner core may contain internal additives (for example, a colorant, a release agent, a charge control agent, and a magnetic powder).

(Binder resin)
In the toner core, generally, the binder resin occupies most (for example, 85% by mass or more) of the components. Therefore, it is considered that the properties of the binder resin greatly affect the properties of the entire toner core. For example, when the binder resin has an ester group, a hydroxyl group, an ether group, an acid group, or a methyl group, the toner core tends to be anionic, and the binder resin has an amino group or an amide group. The toner core tends to be cationic. In order for the binder resin to have strong anionic property, the hydroxyl value of the binder resin (measurement method: JIS (Japanese Industrial Standard) K 0070-1992) and acid value (measurement method: JIS (Japanese Industrial Standard) K 0070-1992) Is preferably 10 mg KOH / g or more, and more preferably 20 mg KOH / g or more.

  As the binder resin, a resin having at least one group selected from the group consisting of an ester group, a hydroxyl group, an ether group, an acid group, and a methyl group is preferable, and a resin having a hydroxyl group and / or a carboxyl group is more preferable. . Binder resins having such functional groups tend to react chemically with the shell material. When such chemical bond occurs, the bond between the toner core and the shell layer becomes strong. Further, as the binder resin, a resin having a functional group containing active hydrogen in the molecule is also preferable.

  In order to improve the fixing property of the toner at the time of high speed fixing, it is preferable that the glass transition point (Tg) of the binder resin is 20 ° C. or more and 55 ° C. or less. The softening point (Tm) of the binder resin is more preferably 100 ° C. or less in order to improve the fixing property of the toner at the time of high-speed fixing. In addition, each measuring method of Tg and Tm is the same method as the Example mentioned later, or its alternative method. The Tg and / or Tm of the resin can be adjusted by changing the types or amounts of the components (monomers) of the resin. The Tg and / or Tm of the binder resin can also be adjusted by combining a plurality of resins.

  As the binder resin of the toner core, a thermoplastic resin (more specifically, the above-mentioned suitable thermoplastic resin etc.) is preferable. In order to improve the dispersibility of the colorant in the toner core, the chargeability of the toner, and the fixability of the toner to the recording medium, it is particularly preferable to use a styrene-acrylic acid resin or a polyester resin as the binder resin.

  When a styrene-acrylic acid resin is used as a binder resin for the toner core, the number average molecular weight (Mn) of the styrene-acrylic acid resin is 2,000 or more and 3,000 or less in order to improve the strength of the toner core and the fixability of the toner. Is preferred. The molecular weight distribution (ratio Mw / Mn of mass average molecular weight (Mw) to number average molecular weight (Mn)) of the styrene-acrylic acid based resin is preferably 10 or more and 20 or less. Gel permeation chromatography can be used to measure Mn and Mw of the styrene-acrylic acid resin.

  When a polyester resin is used as the binder resin of the toner core, the number average molecular weight (Mn) of the polyester resin is preferably 1000 or more and 2000 or less in order to improve the strength of the toner core and the fixability of the toner. The molecular weight distribution (ratio Mw / Mn of mass average molecular weight (Mw) to number average molecular weight (Mn)) of the polyester resin is preferably 9 or more and 21 or less. Gel permeation chromatography can be used to measure the Mn and Mw of the polyester resin.

(Colorant)
The toner core may contain a colorant. As the colorant, known pigments or dyes may be used in accordance with the color of the toner. In order to form a high quality image using toner, the amount of the colorant used is preferably 1 part by mass or more and 20 parts by mass or less, and more preferably 3 parts by mass or more with respect to 100 parts by mass of the binder resin. More preferably, it is 10 parts by mass or less.

  The toner core may contain a black colorant. Examples of black colorants include carbon black. The black colorant may be a colorant toned to black using a yellow colorant, a magenta colorant, and a cyan colorant.

  The toner core may contain color colorants such as yellow colorants, magenta colorants, or cyan colorants.

  As the yellow colorant, for example, one or more compounds selected from the group consisting of condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and arylamide compounds can be used. Examples of yellow colorants include C.I. I. Pigment yellow (3, 12, 13, 14, 15, 17, 62, 74, 83, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155 168, 174, 175, 176, 180, 181, 191 or 194), Naphthol Yellow S, Hansa Yellow G or C.I. I. Bat yellow can be suitably used.

  The magenta colorant is selected, for example, from the group consisting of condensation azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. One or more compounds can be used. Examples of magenta colorants include C.I. I. Pigment red (2, 3, 5, 6, 7, 19, 19, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 150, 166, 169, 177 184, 185, 202, 206, 220, 221 or 254) can be suitably used.

  As the cyan colorant, for example, one or more compounds selected from the group consisting of a copper phthalocyanine compound, an anthraquinone compound, and a basic dye lake compound can be used. Examples of cyan colorants include C.I. I. Pigment blue (1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62 or 66), phthalocyanine blue, C.I. I. Bat blue or C.I. I. Acid blue can be suitably used.

(Release agent)
The toner core may contain a release agent. The release agent is used, for example, for the purpose of improving the fixing property or the offset resistance of the toner. In order to enhance the anionic property of the toner core, it is preferable to produce the toner core using an anionic wax. In order to improve the fixing property or offset resistance of the toner, the amount of the release agent used is preferably 1 part by mass or more and 30 parts by mass or less, and 5 parts by mass with respect to 100 parts by mass of the binder resin. It is more preferable that it is 20 mass parts or less.

  As a mold release agent, for example, low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, or aliphatic hydrocarbon wax such as Fischer-Tropsch wax; oxidized polyethylene wax or block thereof Oxides of aliphatic hydrocarbon waxes such as copolymers; vegetable waxes such as candelilla wax, carnauba wax, wax wax, jojoba wax, or rice wax; animal nature such as bees wax, lanolin or wax wax Waxes; mineral waxes such as ozokerite, ceresin, or petrolatum; waxes based on fatty acid esters such as montanic acid ester wax or castor wax; fatty acids such as deacidified carnauba wax The wax portion of the ester or the whole was deoxygenated can be suitably used. One type of release agent may be used alone, or two or more types of release agents may be used in combination.

  A compatibilizer may be added to the toner core in order to improve the compatibility between the binder resin and the release agent.

(Charge control agent)
The toner core may contain a charge control agent. The charge control agent is used, for example, for the purpose of improving the charge stability or charge rise characteristics of the toner. The charge rising characteristic of the toner is an indicator of whether or not the toner can be charged to a predetermined charge level in a short time.

  By including a negatively chargeable charge control agent in the toner core, the anionic property of the toner core can be enhanced. In addition, the cationic property of the toner core can be enhanced by containing a positively chargeable charge control agent in the toner core. However, in the case where sufficient chargeability is ensured in the toner, it is not necessary to contain the charge control agent in the toner core.

(Magnetic powder)
The toner core may contain magnetic powder. As the magnetic powder, for example, iron (more specifically, ferrite or magnetite etc.), ferromagnetic metal (more specifically cobalt, nickel etc.), alloy containing iron and / or ferromagnetic metal, ferromagnetic Ferromagnetic alloys which have been subjected to chemical treatment (more specifically, heat treatment etc.) or chromium dioxide can be suitably used. One type of magnetic powder may be used alone, or two or more types of magnetic powder may be used in combination.

  In order to suppress the elution of metal ions (for example, iron ions) from the magnetic powder, it is preferable to surface-treat the magnetic powder. In the case where a shell layer is formed on the surface of the toner core under acidic conditions, when metal ions are eluted on the surface of the toner core, the toner cores are easily fixed to each other. By suppressing the elution of metal ions from the magnetic powder, it is considered that the adhesion between toner cores can be suppressed.

[Shell layer]
In the toner particle having the structure (2), the shell layer contains a first resin (a resin containing one or more repeating units having an amide group) and a second resin (one or more repeating units having a quaternary ammonium cation) And a resin). In addition to the first resin and the second resin, the shell layer may further contain a thermosetting resin (more specifically, the above-mentioned suitable thermosetting resin or the like). In order to improve the charge stability and heat resistant storage stability of the toner, one or more thermosetting resins selected from the group consisting of melamine resins, urea resins, and glyoxal resins are used relative to the entire resin. It is preferable to be contained in a shell layer in the ratio of 0.1 to 10 mass%.

(1st resin)
In the configuration (2) described above, as the first resin, a thermoplastic resin (more specifically, the above-mentioned suitable thermoplastic resin etc.) incorporating a repeating unit derived from an amide compound is preferable, and one or more of them are preferable. Particularly preferred is a copolymer of a styrenic monomer (e.g. styrene), one or more acrylic acid monomers (e.g. acrylic esters) and one or more amide compound monomers (e.g. acrylamide).

(2nd resin)
In the above-mentioned constitution (2), as the second resin, a thermoplastic resin (more specifically, the above-mentioned suitable thermoplastic resin etc.) incorporating a repeating unit derived from a quaternary ammonium compound is preferable, and 1 type Particularly preferred is a copolymer of the above quaternary ammonium compound monomer (for example, quaternary ammonium salt) and one or more acrylic acid monomers (for example, acrylic ester).

[External additive]
An external additive may be attached to the surface of the toner base particles. The external additive is used, for example, to improve the flowability or the handleability of the toner. In order to improve the flowability or handleability of the toner, the amount of the external additive is preferably 0.5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the toner base particles. Further, in order to improve the flowability or the handleability of the toner, the particle diameter of the external additive is preferably 0.01 μm or more and 1.0 μm or less.

  As the external additive, particles of silica particles or metal oxides (more specifically, alumina, titanium oxide, magnesium oxide, zinc oxide, strontium titanate, barium titanate or the like) can be suitably used. One type of external additive may be used alone, or a plurality of external additives may be used in combination.

[Method of producing toner]
Hereinafter, an example of a method of manufacturing the toner according to the present embodiment having the above configuration will be described. First, prepare the toner core. Subsequently, the toner core and the shell material are placed in the liquid. In order to form a homogeneous shell layer, it is preferable to dissolve or disperse the shell material in the liquid, for example, by stirring the liquid containing the shell material. Subsequently, the shell material is reacted in the liquid to form a shell layer (cured film) on the surface of the toner core. In order to suppress the dissolution or elution of the toner core components (in particular, the binder resin and the release agent) at the time of shell layer formation, it is preferable to form the shell layer in an aqueous medium. The aqueous medium is a medium containing water as a main component (more specifically, pure water, a mixed solution of water and a polar medium, etc.). The aqueous medium may function as a solvent. The solute may be dissolved in the aqueous medium. The aqueous medium may function as a dispersion medium. The dispersoid may be dispersed in the aqueous medium. As a polar medium in an aqueous medium, for example, an alcohol (more specifically, methanol or ethanol etc.) can be used.

  Hereinafter, the method of manufacturing the toner according to the exemplary embodiment will be further described based on more specific examples. In this example, the toner core is anionic and the shell material (and hence the shell layer) is cationic.

(Preparation of toner core)
In order to easily obtain a suitable toner core, it is preferable to produce the toner core by the aggregation method or the pulverization method, and it is more preferable to produce the toner core by the pulverization method.

  Hereinafter, an example of the pulverization method will be described. First, a binder resin and an internal additive (for example, at least one of a colorant, a release agent, a charge control agent, and magnetic powder) are mixed. Subsequently, the obtained mixture is melt-kneaded. Subsequently, the obtained melt-kneaded product is crushed and classified. As a result, a toner core having a desired particle size is obtained.

  Hereinafter, an example of the aggregation method will be described. First, these particles are coagulated to a desired particle size in an aqueous medium containing fine particles of each of a binder resin, a release agent, and a colorant. Thereby, aggregated particles including the binder resin, the release agent, and the colorant are formed. Subsequently, the obtained aggregated particles are heated to unite the components contained in the aggregated particles. As a result, a dispersion of the toner core is obtained. Thereafter, unnecessary substances (such as dispersants) are removed from the dispersion of the toner core to obtain a toner core.

(Formation of shell layer)
Ion-exchanged water, for example, is prepared as the above-mentioned aqueous medium in which the toner core and the shell material are contained. Subsequently, the pH of the aqueous medium is adjusted to a predetermined pH (for example, a pH selected from 3 or more and 5 or less) using, for example, hydrochloric acid. Subsequently, the toner core, the suspension of the first resin (the liquid containing the first resin particles), and the suspension of the second resin (the second resin particles) in an aqueous medium (for example, acidic ion-exchanged water) whose pH is adjusted. Add the solution containing In addition, if necessary, materials for synthesizing a thermosetting resin may also be added to the aqueous medium.

  The above-mentioned shell material etc. may be added to the aqueous medium at room temperature. However, the molecular weight of the shell layer can be controlled by controlling the temperature of the aqueous medium. The appropriate addition amount of the shell material can be calculated based on the specific surface area of the toner core. In addition to the above-mentioned shell material, a polymerization accelerator may be added to the aqueous medium.

  In order to adhere the shell material uniformly to the surface of the toner core, it is preferable to highly disperse the toner core in a liquid containing the shell material. In order to highly disperse the toner core in the liquid, a dispersant may be contained in the liquid, or the liquid may be stirred using a strong stirring device (for example, “Hi-bis-Disper Mix” manufactured by Primix Corporation). It is also good.

  Subsequently, while stirring the liquid containing the shell material etc., the temperature of the liquid is held at a predetermined speed (for example, a speed selected from 0.1 ° C./min to 3 ° C./min) at a predetermined holding temperature (eg 50) The temperature is raised to a temperature selected from .degree. C. to 85.degree. Further, while stirring the liquid, the temperature of the liquid is maintained at the above-mentioned holding temperature for a predetermined time (for example, a time selected from 30 minutes to 4 hours). While the temperature of the liquid is kept high, the shell material adheres to the surface of the toner core, and the shell material reacts. The shell material reacts to form a film of a shell layer substantially composed of a resin (for example, a first resin and a second resin) on the surface of the toner core.

  The circularity of the toner base particles can be adjusted by changing at least one of the holding temperature and the holding time at the temperature. In order to suppress the elution of the toner core component or the deformation of the toner core, the above-mentioned holding temperature (the temperature of the liquid at the time of forming the shell layer) is preferably less than the glass transition point (Tg) of the toner core. However, the toner core may be deformed by setting the holding temperature above the glass transition point (Tg) of the toner core. When the holding temperature is increased, deformation of the toner core is promoted, and the shape of the toner base particles tends to approach a true sphere. It is desirable to adjust the holding temperature so that the toner base particles have a desired shape. In addition, when the shell material is reacted at high temperature, the shell layer tends to be hard.

  After the shell layer is formed into a film as described above, the dispersion of toner base particles is neutralized using, for example, sodium hydroxide. Subsequently, the dispersion of toner base particles is cooled, for example, to room temperature (about 25 ° C.). Subsequently, the dispersion of toner mother particles is filtered using, for example, a Buchner funnel. As a result, the toner base particles are separated (solid-liquid separation) from the liquid, and wet cake toner base particles are obtained. Subsequently, the obtained wet cake toner base particles are washed. Subsequently, the washed toner base particles are dried. After that, if necessary, the toner base particles and the external additive are mixed using a mixer (for example, an FM mixer manufactured by Nippon Coke Industry Co., Ltd.), and the external additive is attached to the surface of the toner base particles. May be When a spray drier is used in the drying step, the drying step and the external addition step can be simultaneously performed by spraying a dispersion of an external additive (for example, silica particles) on the toner base particles. Thus, a toner containing a large number of toner particles is produced.

  The contents and order of the above-described toner manufacturing method can be arbitrarily changed in accordance with the required toner configuration or characteristics. For example, the timing of adjusting the pH of the liquid (eg, aqueous medium) may be before or after the addition of the above-described shell material etc. (eg, shell material and toner core) to the liquid. Shell materials and the like may be added simultaneously or separately. Further, the step of heating the liquid to the above-mentioned holding temperature may be performed prior to the step of adding a shell material or the like to the liquid. In addition, when the material (for example, shell material) is reacted in the liquid, after the material is added to the liquid, the material may be reacted in the liquid for a predetermined time, or the material is added to the liquid over a long time Then, the material may be reacted in the solution while adding the material to the solution. Also, the shell material may be added to the solution at one time or may be added to the solution in multiple times. The formation method of a shell layer is arbitrary. For example, the shell layer may be formed by any method of in-situ polymerization, in-liquid curing coating method, and coacervation method. The toner may be sieved after the external addition step. Also, unnecessary steps may be omitted. For example, if the reaction of the shell material proceeds well without adjusting the pH of the solution, the pH adjustment step may be omitted. Also, if an external additive is unnecessary, the external addition step may be omitted. When the external additive is not attached to the surface of the toner base particles (the external addition step is omitted), the toner base particles correspond to toner particles. The material for forming the toner core (hereinafter, referred to as toner core material) and the shell material are not limited to the above-described compounds (monomers for synthesizing resin, etc.). For example, if necessary, a derivative of the above-mentioned compound may be used as a toner core material or a shell material, or a prepolymer may be used instead of a monomer. In addition, as a raw material, a salt, an ester, a hydrate, or an anhydride of the compound may be used to obtain the above-described compound. The various materials may be used in the solid state or in the liquid state. For example, a powder of a solid state material may be used, a resin (for example, a masterbatch) into which the material is kneaded may be used, or a solution of the material (a liquid state material dissolved in a solvent) may be used. It may be used or a dispersion of the material (a liquid in which the solid state material is dispersed) may be used. In order to produce the toner efficiently, it is preferable to simultaneously form a large number of toner particles.

  An embodiment of the present invention will be described. Table 1 shows toners A-1 to A-4, B-1, B-2, C-1, and C-2 (positively chargeable toners) according to Examples or Comparative Examples.

Hereinafter, a method of manufacturing toners A-1 to C-2 (respectively positively chargeable toners), an evaluation method, and an evaluation result according to Examples or Comparative Examples will be described in order. In addition, in the evaluation which an error produces, the measurement value of a considerable number which an error becomes small enough was obtained, and the arithmetic mean of the obtained measurement value was made into the evaluation value. The measurement value of the number average particle diameter is a value measured by photographing the particles using a transmission electron microscope (TEM) unless otherwise specified. Further, the measured value of the volume median diameter (D ₅₀ ) is a value measured using “Coulter Counter Multisizer 3” manufactured by Beckman Coulter, Inc., unless specified. Unless otherwise specified, the measured value of zeta potential is a value measured using a zeta potential / particle size distribution analyzer (“Delsa Nano HC” manufactured by Beckman Coulter, Inc.) (specifically, it was measured by the above-mentioned method) Value). Moreover, if the measuring method of Tg (glass transition point) and Tm (softening point) is not each prescribed | regulated, it will be as shown next.

<Method of measuring Tg>
An endothermic curve of a sample (for example, resin) was determined using a differential scanning calorimeter (“DSC-6220” manufactured by Seiko Instruments Inc.). Subsequently, the Tg (glass transition point) of the sample was read from the obtained endothermic curve. The temperature of the change point of specific heat in the obtained endothermic curve (the intersection of the extrapolation line of the baseline and the extrapolation line of the falling line) corresponds to the Tg (glass transition point) of the sample.

<Method of measuring Tm>
A sample (for example, resin) is set in a high-rise type flow tester ("CFT-500D" manufactured by Shimadzu Corporation), and the conditions of the die pore diameter 1 mm, plunger load 20 kg / cm ² , heating rate 6 ° C./min Then, 1 cm ³ of the sample was melted and flowed out to obtain an S-shaped curve (horizontal axis: temperature, vertical axis: stroke) of the sample. Subsequently, the Tm (softening point) of the sample was read from the obtained S-shaped curve. In the obtained S-curve, assuming that the maximum value of the stroke is S ₁ and the stroke value of the baseline on the low temperature side is S ₂ , the value of the stroke in the S-curve is “(S ₁ + S ₂ ) / 2” The corresponding temperature is equivalent to the Tm (softening point) of the sample.

[Method of Manufacturing Toner A-1]
(Preparation of toner core)
750 g of low viscosity polyester resin (Tg = 38 ° C., Tm = 65 ° C.), 100 g of medium viscosity polyester resin (Tg = 53 ° C., Tm = 84 ° C.), high viscosity polyester resin (Tg = 71 ° C., Tm = 120 ° C.) 150 g), 55 g of Carnauba Wax ("Carnauba Wax No. 1" manufactured by Hiroyuki Kato, Inc.), and 40 g of a coloring agent ("KET BLUE 111" manufactured by DIC Corporation, Phthalocyanine Blue), and an FM mixer (Japan Coke Industry Co., Ltd.) It mixed using rotational speed 2400 rpm using the company make).

Subsequently, using a twin-screw extruder ("PCM-30" manufactured by Ikegai Co., Ltd.), the obtained mixture is fed at a material supply rate of 5 kg / hour, shaft rotational speed 160 rpm, set temperature range (cylinder temperature) 100 ° C or higher It melt-kneaded on the conditions of 130 degrees C or less. Subsequently, the obtained melt-kneaded product was cooled, and the cooled melt-kneaded product was roughly crushed using a grinder ("ROTHPLEX (registered trademark) 16/8 type" manufactured by Hosokawa Micron Corporation). Subsequently, the obtained coarsely pulverized material was finely pulverized using a jet mill ("Ultrasonic jet mill I type" manufactured by Nippon Pneumatic Mfg. Co., Ltd.). Subsequently, the obtained pulverized material was classified using a classifier ("Elbow Jet EJ-LABO type" manufactured by Nittetsu Mining Co., Ltd.). As a result, a toner core having a volume median diameter (D ₅₀ ) of 6 μm was obtained.

(Preparation of first shell material)
A 1-L three-necked flask equipped with a thermometer and a stirring blade is set in a water bath, and 875 mL of ion-exchanged water at 30 ° C. and a cationic surfactant (Kohamine (manufactured by Kao Corp.) are contained in the flask. 24P ", component: 75 mL of lauryltrimethylammonium chloride). Thereafter, the temperature in the flask was raised to 80 ° C. using a water bath, and then maintained at that temperature (80 ° C.). Subsequently, two kinds of liquids (the first liquid and the second liquid) were dropped into the flask at 80 ° C. for 5 hours respectively. The first solution was a solution containing 18 g of styrene, 2 g of butyl acrylate and 2 g of acrylamide. The second liquid was a solution in which 0.5 g of potassium persulfate was dissolved in 30 mL of ion exchanged water. Subsequently, the temperature in the flask was kept at 80 ° C. for another 2 hours to polymerize the contents of the flask. As a result, a suspension of resin fine particles (amide group-containing resin) having a solid content concentration of 5% by mass (hereinafter, described as an amide group-containing suspension) was obtained. The number average particle diameter of the resin fine particles contained in the obtained amide group-containing suspension was 26 nm, and the zeta potential at pH 4 was 58 mV. The zeta potential was measured using an ultrasonic particle size distribution zeta potential measuring device ("DT-1200" manufactured by Dispersion Technology).

(Preparation of second shell material)
90 g of isobutanol, 100 g of methyl methacrylate, 35 g of butyl acrylate, and 2- (methacryloyloxy) ethyl in a 1 L three-necked flask equipped with a thermometer, a condenser, a nitrogen introduction pipe, and a stirring blade 30 g of trimethyl ammonium chloride (manufactured by Alfa Aesar) and 6 g of 2,2'-azobis (2-methyl-N- (2-hydroxyethyl) propionamide) ("VA- 086" manufactured by Wako Pure Chemical Industries, Ltd.) Put. Subsequently, the contents of the flask were allowed to react for 3 hours under the conditions of a nitrogen atmosphere and a temperature of 80.degree. Thereafter, 3 g of 2,2'-azobis (2-methyl-N- (2-hydroxyethyl) propionamide) ("VA- 086" manufactured by Wako Pure Chemical Industries, Ltd.) is added to the flask, and a nitrogen atmosphere and temperature are obtained. The contents of the flask were further reacted for 3 hours at 80 ° C. to obtain a polymer solution. Subsequently, the obtained polymer solution was dried at 150 ° C. under a reduced pressure atmosphere. Subsequently, the dried polymer was crushed to obtain a positively chargeable resin.

  Subsequently, 200 g of the positively chargeable resin obtained as described above and ethyl acetate (manufactured by Wako Pure Chemical Industries, Ltd. “acetic acid” are contained in a container of a mixing apparatus (“Hibismix 2P-1 type” manufactured by Primix, Inc.) Ethyl special grade ") 184mL was added. Subsequently, the contents of the container were stirred at a rotational speed of 20 rpm for 1 hour to obtain a highly viscous solution. Thereafter, an aqueous solution such as ethyl acetate (specifically, 18 mL of 1 N hydrochloric acid and a cationic surfactant ("Kortamine 24P" manufactured by Kao Corporation, component: lauryl trimethyl ammonium chloride) and 20 g of ethyl acetate and the like in the obtained high viscosity solution (A solution in which 16 g of “ethyl acetate special grade” manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 562 mL of ion-exchanged water was added. As a result, a suspension of positively chargeable resin fine particles (quaternary ammonium cation-containing resin) having a solid content concentration of 30% by mass (hereinafter, referred to as positively chargeable suspension) was obtained. The number average particle diameter of the resin fine particles contained in the obtained positively chargeable suspension was 35 nm, and the zeta potential at pH 4 was 46 mV. The zeta potential was measured using an ultrasonic particle size distribution zeta potential measuring device ("DT-1200" manufactured by Dispersion Technology).

(Shell layer formation process)
A 1 L three-necked flask equipped with a thermometer and a stirring blade was set in a water bath, and 100 mL of deionized water was placed in the flask. Thereafter, the temperature in the flask was maintained at 30 ° C. using a water bath. Subsequently, dilute hydrochloric acid was added to the flask to adjust the pH of the contents of the flask to 3. Subsequently, 2 g of the first shell material (the amide group-containing suspension prepared in the above procedure) and 30 g of the second shell material (the positively chargeable suspension prepared in the above procedure) were added to the flask.

  Subsequently, 300 g of a toner core (toner core prepared in the above-described procedure) was added to the flask, and the contents of the flask were stirred at a rotational speed of 200 rpm for 1 hour. Thereafter, 300 mL of ion exchanged water was added to the flask. Subsequently, the temperature in the flask was raised to 70 ° C. at a rate of 1 ° C./min while stirring the flask contents at a rotational speed of 100 rpm. Subsequently, the contents of the flask were stirred for 2 hours at a temperature of 70 ° C. and a rotational speed of 100 rpm.

  Subsequently, sodium hydroxide was added to the flask to adjust the pH of the contents of the flask to 7. Subsequently, the contents of the flask were cooled until the temperature reached normal temperature (about 25 ° C.) to obtain a dispersion containing toner base particles.

(Washing process)
The dispersion of the toner base particles obtained as described above was filtered (solid-liquid separation) using a Buchner funnel to obtain wet cake toner base particles. Thereafter, the obtained wet cake toner base particles were re-dispersed in ion exchange water. Further, dispersion and filtration were repeated five times to wash the toner base particles.

(Drying process)
Subsequently, the obtained toner base particles were dispersed in an aqueous ethanol solution having a concentration of 50% by mass. Thereby, a slurry of toner base particles was obtained. Subsequently, the toner base particles in the slurry were subjected to a hot air temperature of 45 ° C. and a blower air volume of 2 m ³ / min using a continuous surface reforming apparatus (“Coatmizer (registered trademark)” manufactured by Freund Corporation). It was allowed to dry. As a result, powder of toner mother particles was obtained.

(External addition process)
Subsequently, the obtained toner mother particles were externally added. Specifically, 100 parts by mass of toner base particles, 1.5 parts by mass of hydrophobic silica fine particles ("AEROSIL (registered trademark) RA-200H" manufactured by Nippon Aerosil Co., Ltd.), and conductive titanium oxide fine particles (manufactured by titanium industry Co., Ltd.) The external additive (silica particles and silica particles and the like) are mixed on the surface of the toner base particles by mixing 1.5 parts by mass of “EC-100” for 5 minutes using a 10 L volume FM mixer (manufactured by Japan Coke Industry Co., Ltd.) The titanium particles were attached. Thereafter, the obtained toner was sieved using a 200 mesh (75 μm mesh) sieve. As a result, Toner A-1 containing a large number of toner particles was obtained.

[Method of Manufacturing Toner A-2 to C-2]
In the method for producing toners A-2 to C-2, the respective addition amounts of the first shell material (amide group-containing suspension) and the second shell material (positively chargeable suspension) in the shell layer forming step are shown in Table 1 The manufacturing method of the toner A-1 was the same as that of the toner A-1 except for the changes as shown in FIG. The second shell material (positively chargeable suspension) was not used in the method of producing each of the toners B-1 and B-2. The first shell material (amide group-containing suspension) was not used in the method of producing each of the toners C-1 and C-2.

[Evaluation method]
The evaluation method of each sample (toner A-1 to C-2) is as follows.

(Toner charge amount)
Using a ball mill, 100 parts by mass of a standard carrier (standard carrier P-01 provided by the Japan Imaging Association) and 10 parts by mass of a sample (toner) were mixed for 30 minutes to prepare a developer for evaluation. The obtained evaluation developer was allowed to stand for 24 hours in an environment of temperature 23 ° C. and humidity 60% RH. After that, when the developer for evaluation is stirred using a shaker mixer ("TURBLER (registered trademark) mixer T2F" manufactured by Willie et Bakofen (WAB) under an environment of a temperature of 23 ° C and a humidity of 60% RH). Charge amount Q ₃ of a sample (toner) in a developer for evaluation at a time of stirring for 3 minutes (hereinafter referred to as a developer after 3 minutes) and a developer for evaluation at a time of stirring for 30 minutes After 30 minutes, the charge amount Q ₃₀ of the sample (toner) in the developer (described as developer) was measured. A Q / m meter ("MODEL 210HS" manufactured by Trek Co., Ltd.) was used to measure the charge amount of the toner. Specifically, the developer for evaluation (the developer after 3 minutes or the developer after 30 minutes) is charged into the measurement cell of the Q / m meter, and only the toner among the developer for evaluation loaded is sieved (wire mesh ) For 10 seconds. Then, the charge amount (μC / g) of the sample (toner) was calculated based on the formula “total amount of electricity of drawn toner (μC) / amount of toner attracted (g)”.

(Toner charge distribution)
As an evaluation machine, a color printer ("FS-C5400 DN" manufactured by KYOCERA Document Solutions Inc.) was used. The developing roller in the developing device of the evaluation machine was provided with a magnet roll and a developing sleeve. The shaft of the magnet roll and the developing sleeve were connected via a flange so that the developing sleeve could rotate around the non-rotating magnet roll. A cylindrical electrode was opposed to the surface of the developing sleeve of the evaluation machine with a gap of 5 mm. One end of a DC power supply was electrically connected to the electrode, and the other end of the DC power supply was electrically grounded.

  Using a ball mill, 100 parts by mass of a standard carrier (standard carrier P-01 provided by the Japan Imaging Association) and 10 parts by mass of a sample (toner) were mixed for 30 minutes to prepare a developer for evaluation. The obtained evaluation developer was stirred for 30 minutes in an environment of a temperature of 23 ° C. and a humidity of 60% RH. As a result, the charge amount of the sample (toner) in the developer for evaluation was saturated. After that, 3 g of the evaluation developer is filled in the developing device of the evaluation machine under an environment of temperature 23 ° C. and humidity 60% RH, and the developing sleeve is rotated at a rotational speed of 500 rpm, (Toner) and a standard carrier. Subsequently, while rotating the developing sleeve at a rotational speed of 500 rpm, only the sample (toner) is electrolytically separated from the surface of the developing sleeve under the condition of an electrolytic intensity of 1 kV / cm using the above DC power supply to collect the sample (toner) did. Then, the collected sample (toner) is set on a charge amount / particle size distribution measuring device ("Espert Analyzer (registered trademark) EST-II" manufactured by Hosokawa Micron Corporation), and the charge amount distribution (vertical) of the sample (toner) Axis: number, horizontal axis: charge amount) was measured. Furthermore, the ratio Y / X (coefficient of variation) between the arithmetic mean value X and the standard deviation Y in the measured charge amount distribution was determined.

(Cover density)
As an evaluation machine, a color printer ("FS-C5400 DN" manufactured by KYOCERA Document Solutions Inc.) was used. 90 parts by mass of a developer carrier (carrier for FS-C5400 DN) and 10 parts by mass of a sample (toner) were mixed for 30 minutes using a ball mill to prepare a two-component developer. The obtained two-component developer was loaded into the developing device of the evaluation machine, and the sample (toner for replenishment) was loaded into the toner container of the evaluation machine.

  After the evaluation machine is turned on and the state of the evaluation machine is stabilized, a sample image including a solid part and a blank part under normal temperature and normal humidity (temperature 23 ° C., humidity 60% RH) environment using the evaluation machine Was formed on an evaluation sheet. Subsequently, fog density (FD) was measured on the formed sample image.

  Next, using the above-mentioned evaluation machine, continuous printing with a printing rate of 5% was performed on 10,000 sheets (A4 size printing paper) under an environment of normal temperature and normal humidity (temperature 23 ° C., humidity 60% RH). . Thereafter, a sample image including a solid part and a blank part was formed on an evaluation sheet. Subsequently, fog density (FD) was measured on the formed sample image.

  In the measurement of fog density (FD) in each of the initial stage and the 10,000 sheets after printing, the image density (ID of the blank area of the formed sample image) (image density of base paper (non-printed evaluation sheet) The value obtained by subtracting ID) corresponds to fog density (FD). A reflection densitometer ("SpectroEye" manufactured by X-Rite Co., Ltd.) was used to measure the image density (ID).

  When the measured fog density (FD) was less than 0.010, it was evaluated as ○ (good), and when it was 0.010 or more, it was evaluated as x (not good).

[Evaluation results]
Table 2 shows the evaluation results for each of the toners A-1 to C-2.

The toners A-1 to A-4 (toners according to Examples 1 to 4) had the above-described configuration (1). Specifically, each of the toners according to Examples 1 to 4, the charge amount Q _3, was charged amount Q ₃₀ or more and 20 [mu] C / g or more. Also, the arithmetic mean value X and the standard deviation Y in the charge amount distribution of the toner satisfy the relationship of the formula “Y / X ≦ 3.5”. In any of the toners according to Examples 1 to 4, the zeta potential of pH 4 of the toner core was smaller than 0 V, and the zeta potential of pH 4 of toner particles was larger than 0 V. In any of the toners according to Examples 1 to 4, the ratio of the first resin particles in the shell layer is 0.5% by mass or more and 5.0% by mass or less, and the ratio of the second resin particles in the shell layer is It was 95.0 mass% or more and 99.5 mass% or less. For example, in the toner according to Example 2, as shown in Table 1, the ratio of the first resin particles in the shell layer is 2.2 mass% (≒ 100 × 2 × 0.05 / 4.6), And, the proportion of the second resin particles in the shell layer was 97.8 mass% (≒ 100 × 15 × 0.30 / 4.6). In the toner according to Example 3, as shown in Table 1, the ratio of the first resin particles in the shell layer is 0.6 mass% (% 100 × 1 × 0.05 / 9.05), And, the proportion of the second resin particles in the shell layer was 99.4 mass% (≒ 100 × 30 × 0.30 / 9.05). As shown in Table 2, by using each of the toners according to Examples 1 to 4, stable, high-quality (specifically, low fog density) images could be formed.

  As shown in Table 2, in the toners B-1 and B-2 (the toners according to Comparative Examples 1 and 2), the fogging density was higher than that of the toners according to Examples 1 to 4, respectively. The reason is considered to be that the reversely charged toner is generated.

  As shown in Table 2, in the toners C-1 and C-2 (the toners according to Comparative Examples 3 and 4), the fogging density was higher than that of the toners according to Examples 1 to 4, respectively. The reason is considered to be that the charge amount distribution of each of the toners according to Comparative Examples 3 and 4 is too broad.

  The positively chargeable toner according to the present invention can be used, for example, to form an image in a copier, a printer, or a multifunction machine.

Claims (6)

A positively chargeable toner comprising a plurality of toner particles comprising a core and a shell layer formed on the surface of the core,
The shell layer has a single layer structure containing a first resin containing one or more repeating units having an amide group and a second resin containing one or more repeating units having a quaternary ammonium cation,
When a mixture of 100 parts by mass of a standard carrier and 10 parts by mass of the toner is stirred using a shaker mixer under an environment of temperature 23 ° C. and humidity 60% RH, the charge amount of the toner at the time of stirring for 3 minutes Is equal to or greater than the charge amount of the toner at the time of stirring for 30 minutes and is equal to or greater than 20 μC / g,
When the charge amount distribution of the toner carried on the developing roller is measured, the arithmetic mean value X and the standard deviation Y in the charge amount distribution measured have the relationship of the formula “Y / X ≦ 3.5”. It meets,
The shell layer includes a first resin particle substantially composed of the first resin, and a second resin particle substantially composed of the second resin,
The proportion of the first resin particles in the shell layer is 0.5% by mass or more and 5.0% by mass or less, and the proportion of the second resin particles in the shell layer is 95.0% by mass or more and 99.5% Positively chargeable toner having a mass% or less . Wherein the first resin is a thermoplastic resin incorporating repeating units derived from an amide compound, said second resin is a thermoplastic resin incorporating repeating units derived from quaternary ammonium compounds, in claim 1 Positively chargeable toner as described. The second resin is a copolymer of one or more quaternary ammonium compound monomer and one or more acrylic monomers, positively chargeable toner according to claim 1 or 2. The positively chargeable toner according to any one of claims 1 to 3 , wherein the first resin has a repeating unit derived from styrene, butyl acrylate and acrylamide. The second resin, methyl methacrylate, having a repeating unit derived from butyl acrylate and 2- (methacryloyloxy) ethyl trimethyl ammonium chloride, a positively chargeable toner according to any one of claims 1-4. A positively chargeable toner comprising a plurality of toner particles comprising a core and a shell layer formed on the surface of the core,
The shell layer has a single layer structure containing a first resin containing one or more repeating units having an amide group and a second resin containing one or more repeating units having a quaternary ammonium cation,
When a mixture of 100 parts by mass of a standard carrier and 10 parts by mass of the toner is stirred using a shaker mixer under an environment of temperature 23 ° C. and humidity 60% RH, the charge amount of the toner at the time of stirring for 3 minutes Is equal to or greater than the charge amount of the toner at the time of stirring for 30 minutes and is equal to or greater than 20 μC / g,
When the charge amount distribution of the toner carried on the developing roller is measured, the arithmetic mean value X and the standard deviation Y in the charge amount distribution measured have the relationship of the formula “Y / X ≦ 3.5”. Meet
The positively chargeable toner , wherein the first resin is a copolymer of at least one styrenic monomer, at least one acrylic acid monomer, and at least one amide compound monomer.